Head in the clouds

It’s as easy as adding the following to your .ebextensions folder:

files:
  "/usr/local/bin/acronjob.sh":
    mode: "000755"
    owner: root
    group: root
    content: |
      #!/bin/bash
      root . /command/to/run

Running a cron on one server?

files:
  "/usr/local/bin/test_cron.sh":
    mode: "000755"
    owner: root
    group: root
    content: |
      #!/bin/bash
      INSTANCE_ID=`curl http://169.254.169.254/latest/meta-data/instance-id 2>/dev/null`
      REGION=`curl -s http://169.254.169.254/latest/dynamic/instance-identity/document 2>/dev/null | jq -r .region`

       # Find the Auto Scaling Group name from the Elastic Beanstalk    environment
       ASG=`aws ec2 describe-tags --filters "Name=resource-id,Values=$INSTANCE_ID" \
--region $REGION --output json | jq -r '.[][] | select(.Key=="aws:autoscaling:groupName") | .Value'`

       # Find the first instance in the Auto Scaling Group
       FIRST=`aws autoscaling describe-auto-scaling-groups --auto-scaling-group-names $ASG \
--region $REGION --output json | \
jq -r '.AutoScalingGroups[].Instances[] | select(.LifecycleState=="InService") | .InstanceId' | sort | head -1`

      # If the instance ids are the same exit 0
      [ "$FIRST" = "$INSTANCE_ID" ]

  "/usr/local/bin/acronjob.sh":
    mode: "000755"
    owner: root
    group: root
    content: |
      #!/bin/bash
      /usr/local/bin/test_cron.sh || exit
      root . /command/to/run

Crons not running on Amazon Linux?

When placing cronjobs in /etc/cron.d do not use dots or hyphens in the file name.